Module 5: Homeland Security: Washington DC Crime Mapping

This week we moved into utilizing GIS to benefit law enforcement. 

Law enforcement agencies daily responsibility of protecting life and property while keeping the peace in their communities:  responding to crime reports, investigating criminal activities to apprehend those responsible, thwarting would be criminal activities, monitoring known criminals 

GIS provides a visual, spatial means of displaying data, allowing law enforcement agencies to make informed decisions more quickly.  GIS can assist law enforcement with by helping to identify an incident location, generate a location report, visualize an incident location, analyze an impacted area and coordinate resources.  

Crime Analysis is the qualitative and quantitative study of crime and police related information in combination with socio-demographic and spatial factors.  The primary goals of crime analysis are to apprehend criminals, prevent crime, reduce disorder, and evaluate organizational procedures.

In lab this week we establish workspace environments (view-data frame properties-coordinate system) and tool environments (right click in the toolbox menu, outside of a tool, select environments-expand workspace-set current workspace, output coordinate system set to same as display, for processing extent set to same as Washington DC layer, raster analysis setting set raster cell size to 73, set the mask to Washington DC).  We utilized Address Locator to create points for the police stations and added points by hand for the 3 unmatched addresses by utilizing google map to obtain the location.  We added a filed to attribute table and utilized the field calculator and entered the formula.  We utilized the multi ring buffer tool to set buffers around police stations.  We joined layers based on spatial location.  We utilized kernel density tool from spatial analyst toolset to create crime densities for burglaries, homicides and sex abuse crimes.  

The first map has a TON of information - much more than I would have thought possible:

• population density choropleth by census block group
• location of police stations with graduated symbols showing percent of crimes being handled in that station
• 3 ring police station buffer transparency overlay
• points of the crimes
• Summary Graph showing the count by type of crimes
• Each station is labeled with the name and percent of total crimes that station handeled
• Proposed location of a new station based on station buffers, crimes, and neighboring station percent of crimes.

The second map has 3 data frames that show the results of the kernel density for burglaries, homicides and sex abuse crimes.  Each of the density results is shown as a transparency over the population density choropleth.  The neighboring results allow for comparison of each crimes hotspots.